The present invention addresses several problems found in large wireless security systems. The first problem is caused by wireless security systems that utilize a large number of wireless motion detector transmitters. When the security system is in the armed state, these motion detector devices are not activated due to the lack of people moving about in the protected premises. However, when the security system is in the disarmed state, these motion detector devices are constantly transmitting signals to the associated RF receivers due to their detection of people moving within the protected premises while the control panel is disarmed. Since the control panel is disarmed, these transmitted signals have no significance and are therefore discarded by the control panel. However, the frequent signal transmissions from these types of transmitters cause a large amount of unnecessary signal traffic on the wired communication bus connecting the control panel to the RF receivers. In effect, these unnecessary signal transmissions hamper the ability of the control panel to service signals transmitted from other devices, wired and wireless, which need immediate attention even when the system is disarmed.
It is therefore an object of the present invention to provide a wireless security system that overcomes the problems of the prior art mentioned above.
It is also an object of the present invention to provide such a security system that ameliorates the unwanted processing requirements on the control panel due to motion detector transmissions (and other non-essential transmissions) that occur during the system disarmed state.
In particular, it is an object of the present invention to provide such a security system that can process the received messages at the receiver module and filter the messages that originate from non-essential transmitters, so that such non-essential messages are not passed on to the control panel when in the disarmed state.
The second problem found in large wireless security systems relates to the use of a large number of wireless receivers in a system that are connected to the control panel. Although most currently available wireless security systems are limited to the use of not more than two receivers on a single system, it is desired to be able to use more receivers in larger premises. That is, this limitation is restrictive in relatively large systems where more than two RF receivers are necessary in order to properly detect signals from all of these transmitting devices distributed over a very wide area in the system. For example, in a six-story building containing, twenty transmitting devices per floor, it would be best to have one RF receiver located on each floor in order to avoid large amounts of RF transmission loss between multiple floors which are generally constructed of steel-enforced flooring materials. However, placing 6 RF receivers on the same security control's communication bus makes it almost impossible for the control to differentiate between recent and previous transmission events from a given transmitting device or to identify a single transmission event reaching the control via each of some of the receivers at slightly different time intervals. This is further aggravated by the fact that in most wireless systems, a given transmission event involves the transmission of a multiple number of identical transmitted messages over a period of 2-4 seconds in order to ensure adequate reception by a given receiver. For example, it may be desirable to transmit messages in a sextet format, where the (usually) identical message is transmitted six times over the 2-4 second period to ensure proper reception by the control panel.
It is therefore a further object of the present invention to provide such a security system that allows the control panel to determine if a message is received out of sequence and to ignore its contents, accordingly.
The third problem found in large wireless security systems relates to the additional traffic generated on the control's communication bus when a multiplicity of RF receivers are connected. In the above example using 6 RF receivers, a single sensor event could cause the generation of up to six identical messages to the control. These additional messages could cause the control's communication bus to become overloaded.
It is therefore a further object of the present invention to provide such a security system that allows each receiver to monitor the transmissions between the control panel and the other receivers to determine if a message has already been transmitted to and acknowledged by the control panel and avoid repetitive transmissions to the control panel.
The fourth problem encountered relates to the tedious and time-consuming task required of the system installer in programming responses to be carried out by the control panel when it receives a message from a given transmitter in the system. That is, at the time of installation, the installer must assign a particular response type to a particular serial or identification number for each transmitter in the system. Examples of response type are fire, perimeter, entry/exit door, panic, interior (motion), and interior-follower (motion looking at the entry door). During the control panel programming, the installer will assign a panel fire response to the smoke detectors, a burglary response type to perimeter serial numbers, etc. In some control panels, there may be 256 zones that need to be programmed, which is time consuming and error prone.
It is therefore desired to provide a methodology whereby the control panel can determine the type of product from the received message and execute a response accordingly, without having to carry out programming for each transmitter as in the prior art.